A Massachusetts law that authorizes a 35-foot, speech-free buffer zone around abortion clinics appears to be in serious jeopardy following a contentious hour-long hearing at the US Supreme Court on Wednesday.

The state law was passed in 2007 in an effort to prevent antiabortion protesters from obstructing clinic entrances and harassing or intimidating patients.

The case before the high court involves a group of antiabortion counselors who seek the opportunity to speak quietly with women who are about to have an abortion.

Their goal is clear; they want to talk them out of ending their pregnancy. And their tactics involve a decidedly undramatic approach that would never make an evening newscast. A lawyer described the tactic as “quiet conversation.”

Their lawyer, Mark Rienzi, argues that the First Amendment’s protects their right to engage in conversations on a public sidewalk – including a public sidewalk in front of an abortion clinic.

This approach of focusing on non-confrontational aspects of antiabortion speech makes the case different than other abortion clinic obstruction cases heard by the high court. And it highlights the difficulty of enacting a broad prohibition of speech within a 35-foot zone without also treading on someone’s free speech rights.

At one point during the argument, Assistant Massachusetts Attorney General Jennifer Grace Miller compared the area around an abortion clinic entrance to a “goalie’s crease,” the zone marked off in front of a goal in ice hockey.

Ms. Miller’s descriptions of clinic protests evoked chaotic scenes of shouting, shoving, and swearing, not unlike a kind of sidewalk version of a Boston Bruins hockey game.

“This is not a protest case,” Justice Antonin Scalia objected at one point. “These people don’t want to protest abortion. They want to talk to the women who are about to get abortions and try to talk them out of it.”

He added: “If it was a protest, keeping them back 35 feet might not be so bad. They can scream and yell and hold up signs from 35 feet. But what they can’t do is try to talk the woman out of the abortion.”

“It is a counseling case,” Scalia said, “not a protest case.”

Miller responded that even those who wanted to talk quietly with the patients were adding to the congestion around the clinic entrance.

Justice Stephen Breyer attempted to come to Miller’s aid by suggesting to his fellow justices that perhaps the quiet conversation and the more disruptive shouting were co-mingled activities and that it would thus be exceedingly difficult to regulate separately with any precision.

Justice Anthony Kennedy responded with a question. What if an elderly woman wanted to counsel patients before they obtain an abortion and had been successful in doing so before the buffer zone law had been enacted, he asked. And what if after the law she was unable to talk to even a single patient?

Justice Kennedy asked whether a law could be written to protect that kind of activity while still preventing obstructions outside clinics.

Rather than exploring Kennedy’s concern, Miller rejected it.

“No one is guaranteed any specific form of communication,” Miller said. “There is no guarantee … to close, quiet conversations.”

Kennedy responded: “Do you want me to write an opinion and say there is no free speech right to quietly converse on an issue of public importance?”

It is the kind of comment justices offer now and then. Such a comment about writing an opinion that will do such and such is usually a clear sign that the arguing counsel has gone seriously off the rails.

“In speech cases,” Kennedy said, “when you address one problem, you have a duty to protect speech that’s lawful.”

Even Justice Elena Kagan, a pro-choice stalwart, expressed concern about the broad scope of the Massachusetts law.

After Miller suggested that it wasn’t much of a burden for the challengers to move “back a few feet” from the clinic entrance, Justice Kagan responded: “Well, it’s more than a few feet.”

“Thirty-five feet is a ways. It’s from this bench to the end of the court,” she said. “That’s a lot of space.”

Earlier in the argument, the lawyer for the challengers, Mr. Rienzi, was asked about the practical implications of moving protesters away from a particular location.

Rienzi drew an analogy to his own argument before the high court. “If you sent me 35 feet further back and asked me to make my argument from there…”